2020-10-10 23:08:28

by Hedi Berriche

Subject: [PATCH v3 0/1] PCI/ERR: fix regression introduced by 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")

- Changes since v2:

* set status to PCI_ERS_RESULT_RECOVERED, in case of successful link
reset, if and only if the initial value of error status is
PCI_ERS_RESULT_DISCONNECT or PCI_ERS_RESULT_NO_AER_DRIVER.

- Changes since v1:

* changed the commit message to clarify what broke post commit 6d2c89441571
* dropped the misnomer post_reset_status variable in favour of a more natural
approach that relies on a boolean to keep track of the outcome of reset_link()

After commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
pcie_do_recovery() no longer calls ->slot_reset() in the case of a successful
reset which breaks error recovery by breaking driver (re)initialisation.

Cc: Russ Anderson <[email protected]>
Cc: Kuppuswamy Sathyanarayanan <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Ashok Raj <[email protected]>
Cc: Joerg Roedel <[email protected]>

Cc: [email protected] # v5.7+

---
Hedi Berriche (1):
PCI/ERR: don't clobber status after reset_link()

drivers/pci/pcie/err.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--
2.28.0

2020-10-10 23:15:32

by Hedi Berriche

Subject: [PATCH v3 1/1] PCI/ERR: don't clobber status after reset_link()

Commit 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
broke pcie_do_recovery(): updating status after reset_link() has the ill
side effect of causing recovery to fail if the error status is
PCI_ERS_RESULT_CAN_RECOVER or PCI_ERS_RESULT_NEED_RESET as the following
code will *never* run in the case of a successful reset_link()

177 if (status == PCI_ERS_RESULT_CAN_RECOVER) {
...
181 }

183 if (status == PCI_ERS_RESULT_NEED_RESET) {
...
192 }

For instance in the case of PCI_ERS_RESULT_NEED_RESET we end up not
calling ->slot_reset() (because we skip report_slot_reset()) thus
breaking driver (re)initialisation.

Don't clobber status with the return value of reset_link(); set status
to PCI_ERS_RESULT_RECOVERED, in case of successful link reset, if and
only if the initial value of error status is PCI_ERS_RESULT_DISCONNECT
or PCI_ERS_RESULT_NO_AER_DRIVER.

Fixes: 6d2c89441571 ("PCI/ERR: Update error status after reset_link()")
Signed-off-by: Hedi Berriche <[email protected]>
Cc: Russ Anderson <[email protected]>
Cc: Kuppuswamy Sathyanarayanan <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Ashok Raj <[email protected]>
Cc: Joerg Roedel <[email protected]>

Cc: [email protected] # v5.7+
---
drivers/pci/pcie/err.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index c543f419d8f9..2730826cfd8a 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -165,10 +165,13 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
pci_dbg(dev, "broadcast error_detected message\n");
if (state == pci_channel_io_frozen) {
pci_walk_bus(bus, report_frozen_detected, &status);
- status = reset_link(dev);
- if (status != PCI_ERS_RESULT_RECOVERED) {
+ if (reset_link(dev) != PCI_ERS_RESULT_RECOVERED) {
pci_warn(dev, "link reset failed\n");
goto failed;
+ } else {
+ if (status == PCI_ERS_RESULT_DISCONNECT ||
+ status == PCI_ERS_RESULT_NO_AER_DRIVER)
+ status = PCI_ERS_RESULT_RECOVERED;
}
} else {
pci_walk_bus(bus, report_normal_detected, &status);
--
2.28.0